The present invention relates to a tree clamp such as may be used in lifting, moving and transplanting trees.
Various types of apparatus have been devised for use in the lifting, moving and transplanting of trees. For example, U.S. Pat. No. 357,197, issued Feb. 8, 1887 to Harsin, illustrates one type of a device including several connectable plate members, which may be joined together to fully enclose the base of the tree, its roots, and the earth immediately surrounding them. The ground about the base of the tree is excavated, leaving a trench surrounding the base. An annular ring is clamped about the base of the trunk, and the various plate sections are fitted about the roots of the tree. The sections are connected to each other, as well as fastened to the ring about the tree trunk, thereby fully enclosing the tree base and roots within a rigid structure.
There are several disadvantages associated with the type of device illustrated by the Harsin patent. By providing for substantially full enclosure of the roots of the tree, the size of tree with which the device may be used is considerably limited. Further, by attaching each of the sections to its immediately adjoining sections, as well as to a central ring, the attachment and removal of the device is relatively complex. Additionally, no ready means for removing the tree from the ground following installation of the device is provided, short of dragging the tree from the excavation.
In U.S. Pat. No. 2,707,846, issued May 10, 1955 to Beseler, a sling for use in transplanting trees is disclosed. In using the sling, the earth about the tree is again excavated, so as to leave the tree base, roots and earth surrounding them in the form of a ball. A plurality of vertically extending flexible strap members are placed about the ball, and are joined together at their bottom ends by a combination of additional flexible straps and lengths of chain. Each vertical strap further has a ring at its upper end, and a chain is threaded through each ring, tightened and connected to itself such that the sling completely encircles the ball of the tree. A yoke member is then connected to the upper chain along one side of the tree trunk. The yoke is connected to a winch, crane, or the like for lifting the tree from the ground.
While the Beseler device overcomes one disadvantage of the Harsin device in that it is readily adaptable to any size tree, it too possesses several disadvantages. Depending on the size of the tree to be moved, the proper number of vertical straps must be connected together in an approximately equally spaced relationship. Further, the upper chain must be threaded through the rings of the vertical straps, and must be securely tightened about the ball. Thus, positioning of the sling is a relatively time-consuming process. Further, lifting the tree by the single yoke will result in the tree pivoting about the yoke as it is lifted from the ground. This can result in tree branches moving against the chain or cable connecting the yoke to the lifting mechanism, or against nearly obstacles, potentially causing broken branches and damage to the tree. Additionally, by having the tree in a non-vertical alignment and freely pivotal while lifted, accurate positioning of the tree at the transplant site is made more difficult.
A third device for use with a method of transplanting trees is shown in U.S. Pat. No. 3,017,719, issued Jan. 23, 1962 to Sigle et al. The disclosed apparatus represents a portion of a vehicle, which includes a lifting mechanism substantially similar to that found on a standard lift truck. A vertically movable platform is provided, to which is mounted a support for a plurality of vertically extendable blades. The vehicle may be moved into place so that the blades surround the tree to be transplanted, whereupon the blades may be either oscillated or fully rotated about the tree. As the blades cut into the earth, they are extended downwardly, such that they effectively sever the tree base, roots and earth surrounding them from the remainder of the ground. The platform may then be lifted, whereupon the blades lift the tree from the ground.
Because the operation of the Sigler et al apparatus is performed substantially completely by the machine, it does possess the advantage of ease of operation. It will be readily recognized, however, that the relative complexity of the machinery results in an expensive piece of equipment, a serious disadvantage in comparison to the other disclosed devices. Further, the care and maintenance of the equipment is also significantly greater.
What is needed, therefore, is a device for supporting a tree to enable its lifting during the transplanting of the tree. Such a device should be relatively simple to use, and should be capable of relatively quick attachment to and disconnection from the tree. The device should be capable of use with a wide range of tree sizes. The device should also be useable in conjunction with a readily available lifting mechanism for lifting the tree in a stable manner. Further, the device should be of relatively low cost, and require relatively little care and maintenance.